This invention relates to an operation control device for an in-cylinder injection engine and more particularly to an improved fuel injection system for an engine and method of operating it.
It has been recognized that there are certain advantages in providing direct cylinder injection. With in-cylinder or direct injection engines, it is possible to operate the engine on a leaner fuel and air mixture than with an engine wherein the fuel and air is mixed before it is admitted to the combustion chamber. With direct cylinder injection, it is possible to have a stratification effect wherein there will be a stoichiometric charge at the spark plug at the time ignition is commenced wherein the remainder of the combustion chamber is charged with primarily pure air. The advantages of such systems are obvious. However, with certain types of engines and under certain conditions, it is desirable to provide additional fuel to the combustion chamber through the induction system. For example, with two-cycle crankcase compression engines there is a desirability of providing a portion of the fuel charge for the engine to the combustion chamber through the induction system including the crankcase. This will assist in cooling under high speed, high load conditions.
There may be instances wherein it is possible to determine that the main, direct cylinder injector has malfunctioned. When this occurs, it may be desirable to discontinue the supply of fuel from this injector.
It is, therefore, a principal object of this invention to provide an injection system for an internal combustion engine having a direct cylinder injector and an induction system injector and wherein means are provided for detecting an abnormality in the main injector and in that event the main injector may be shut down.
It is a further object of this invention to provide an improved injection system for an engine including both direct and manifold injection systems.
When direct cylinder injection is employed, it has been the practice to open the throttle valve to a greater extent than is done when the fuel/air mixture is admitted to the combustion chamber through the induction system. That is, when only direct cylinder injection is employed, it is the normal practice to employ greater throttle valve settings than when other forms of fuel delivery are employed. Therefore, if the system is provided with both direct main fuel injectors and manifold injectors and the fuel supply is provided only by the manifold injector in the event of malfunction of the main injector, the engine may experience a sudden speed increase.
It is, therefore, a further object to this invention to provide an improved throttle control arrangement for an engine having both main direct fuel injection and manifold fuel injection.